Pallet positioning station and associated methods

ABSTRACT

A pallet positioning station for positioning a pallet to be impacted by a pallet impact station includes a pallet push arm assembly adjacent the pallet impact station. The pallet push arm assembly includes a pallet push arm movable between a retracted position and a pallet positioning position. A controller is configured to move the pallet push arm to the retracted positions to receive the pallet for positioning, and move the pallet push arm to the pallet positioning position to position the pallet towards the pallet impact station for impact.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/295,158filed Mar. 7, 2019 which is a continuation of application Ser. No.15/656,159 filed Jul. 21, 2017, now U.S. Pat. No. 10,252,867, which arehereby incorporated herein in their entireties by reference.

TECHNICAL FIELD

The present invention relates to the field of pallets, and moreparticularly, to a pallet positioning system for use with a palletimpact station.

BACKGROUND

Wooden pallets are used to transport a variety of bulk goods andequipment as required in manufacturing and warehousing operations. Inhigh volume industries, pallet pools provide a lower total industry costthan one-way pallets. The current assignee of the present inventionrecognizes the benefits of pooled pallets, and currently has overseveral hundred million pallets that are pooled each year.

Conventional wood pallets include a base layer and a cargo layerseparated therefrom by support blocks. The support blocks form a gapbetween the base and cargo layers for receiving a lifting member.Traditionally, the base and cargo layers respectively have end deckboards assembled on connector boards that run the full length or widthof the pallet.

As one might expect, wooden pallets are subject to damage in use thatoccurs from handling with forklifts or other like equipment. To move thewooden pallets with cargo thereon, forklift tines from a forklift, forexample, are inserted into the gap between the base and cargo layers. Ifthe forklift tines are not properly aligned within the gap, they maycrash into the support blocks or into the end deck boards or connectorboards in the base or cargo layers. Impacts such as this weaken thepallet and greatly shorten the life cycle of the pallet, thereby causingthe pallet to be repaired more frequently and/or removed from servicebefore its anticipated life cycle has been reached.

Consequently, there is a need to test the life cycle of a pallet. Thisis particularly helpful when design changes are being made to a pallet.If the design changes are determined to increase the life cycle of thepallet, then the redesigned pallets may be inserted into the palletpool. The difficulty in simulating the life cycle of a pallet is to beable to repeatedly strike the pallet in a precise location with apredetermined amount of energy. In addition, if the pallet is not squareprior to impact, or if the pallet is not repositioned prior to receivinganother impact, then the amount of energy striking the pallet varies.This degrades the accuracy of the life cycle testing of the pallet.

SUMMARY

A pallet positioning station for positioning a pallet to be impacted bya pallet impact station includes a pallet push arm assembly adjacent thepallet impact station. The pallet push arm assembly includes a palletpush arm movable between a retracted position and a pallet positioningposition. A controller is configured to move the pallet push arm to theretracted positions to receive the pallet for positioning, and move thepallet push arm to the pallet positioning position to position thepallet towards the pallet impact station for impact.

The pallet positioning station may further include a pallet liftassembly comprising a lift grate moveable between a retracted positionand an extended position. The controller may be further configured tomove the lift grate to the retracted position to receive the pallet forpositioning, and move the lift grate to the extended position when thepallet is to be positioned for impact by the pallet impact station.

The controller may be further configured to position the pallet towardsthe pallet impact station for impact until the pallet is aligned with animpact reference plane. The pallet positioning station may furtherinclude a frame adjacent the pallet impact station, with the pallet liftassembly being carried by the frame.

The lift grate may include a plurality of spaced apart elongated liftelements, with each respective lift element sized to fit between twoadjacent rollers of a roller conveyor.

The pallet lift assembly may further include a plurality of verticalactuators for moving the lift grate when activated via the controllerbetween the retracted position and the extended position.

The pallet lift assembly may further include at least one horizontalactuator for moving the lift grate in a horizontal direction between animpact reference plane and the pallet push arm. The controller may befurther configured to move the lift grate in the horizontal directiontowards the pallet push arm so that the pallet contacts the pallet pusharm before the pallet push arm is moved to the pallet positioningposition.

The pallet lift assembly may further include a radius arm rotatablycoupled to a frame, and a link extending between the radius arm and thelift grate. The at least one horizontal actuator may extend between theframe and the radius arm.

The controller may be further configured to operate the plurality ofvertical actuators and the at least one horizontal actuatorsimultaneously. The plurality of vertical actuators and the at least onehorizontal actuator each comprises a hydraulic actuator.

The pallet push arm assembly may further include a pair of spaced apartradius arms rotatably coupled to a frame, a pair of spaced apart linksextending between the pair of radius arms and the pallet push arm, and apair of actuators extending between the frame and the pair of radiusarms for moving the pallet when activated via the controller.

The pallet positioning station may further include a frame adjacent thepallet impact station, with the pallet push arm assembly being carriedby the frame.

The pallet positioning station may further include a movement sensorconfigured to generate a signal corresponding to movement of the palletpush arm when in the pallet positioning position. The controller may befurther configured to move the pallet push arm in the pallet positioningposition until the generated signal reaches a predetermined value, withthe predetermined value corresponding to when an impact side of thepallet is aligned with an impact reference plane. The movement sensormay include a linear variable differential transformer (LVDT) extendingbetween the frame and one of the radius arms.

The controller may be further configured to move the pallet push armback to the retracted position after an impact side of the pallet isaligned with an impact reference plane.

The pallet may carry a unit load during impact with the pallet impactstation. The pallet impact station includes a stationary unit load pushbar adjacent an impact reference plane. As the controller moves thepallet push arm in the pallet positioning position to move the pallet,the unit load contacts the stationary unit load push bar as an impactside of the pallet continues to move towards the impact reference plane.

Yet another aspect is directed to a pallet positioning station thatincludes a pallet push arm movable between a retracted position and apallet positioning position, and a movement sensor configured togenerate a signal corresponding to movement of the pallet push arm whenin the pallet positioning position. A controller may be configured tomove the pallet push arm to the retracted position to receive the palletfor positioning, and move the pallet push arm to the pallet positioningposition to position the pallet towards a pallet impact station based onthe generated signal reaching a predetermined value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a pendulum impact station with the carriageassembly in the raised position in accordance with the presentinvention.

FIG. 2 is a side view of a pallet positioning station with a palletpositioned for impact in accordance with the present invention.

FIG. 3 is a top view of the pendulum impact station illustrated in FIG.1.

FIG. 4 is a side view of the pendulum impact station illustrated in FIG.1 with the carriage assembly in the lowered position.

FIG. 5 is a rear view of the pendulum impact station illustrated in FIG.4.

FIG. 6 is a more detailed top view of the carriage assembly illustratedin FIG. 1.

FIG. 7 is a partial side view of the carriage assembly illustrated inFIG. 6.

FIGS. 8-12 are side views of the latching mechanism for the carriageassembly illustrated in FIG. 1 at different positions.

FIG. 13 is an end view of the latching mechanism illustrated in FIG. 8.

FIG. 14 is a side view of the braking mechanism for the carriageassembly illustrated in FIG. 1.

FIG. 15 is a partial end view of the braking mechanism illustrated inFIG. 14.

FIG. 16 is a side view of the pallet positioning station illustrated inFIG. 2 with the lifting grate in a retracted position.

FIG. 17 is an end view of the pallet positioning station illustrated inFIG. 16.

FIG. 18 is a top view of the lifting grate as illustrated in FIG. 17separated from the roller conveyor.

FIG. 19 is an end view of the lifting grate illustrated in FIG. 18.

FIG. 20 is a top view of the lifting grate as illustrated in FIG. 17positioned between the rollers on the roller conveyor with the palletremoved.

FIG. 21 is a side view of the pallet positioning station illustrated inFIG. 2 with the lifting grate in an extended position.

FIG. 22 is an end view of the pallet positioning station illustrated inFIG. 21.

FIG. 23 is a side view of the pallet positioning station illustrated inFIG. 21 with the lifting grate moving the test pallet to be squared withthe pallet push arm.

FIG. 24 is a side view of the pallet positioning station illustrated inFIG. 23 with the pallet push arm assembly moving the test pallet towardsthe impact reference plane.

FIG. 25 is a top view of the test pallet with the unit loads thereon incontact with the stationary unit load push bar.

FIG. 26 is a partial side view of the test pallet and unit loadsillustrated in FIG. 25.

FIG. 27 is a partial side view of the pallet tester with the carriageassembly contacting the test pallet in accordance with the presentinvention.

FIG. 28 is a flowchart illustrating a method for operating the palletimpact station illustrated in FIG. 1.

FIG. 29 is a flowchart illustrating a method for operating the palletpositioning station illustrated in FIG. 2.

FIG. 30 is a flowchart illustrating a method for testing a pallet usingthe pallet tester illustrated in FIGS. 1 and 2.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

A life cycle pallet tester includes a pallet impact station 100 asillustrated in FIG. 1, and a pallet positioning station 200 asillustrated in FIG. 2. The pallet positioning station 200 is configuredto repeatedly position a test pallet 50 at a same location on a rollerconveyor 80 before each impact by the pallet impact station 100. Thepallet impact station 100 is configured to impact the test pallet 50with a programmable amount of force at a precise location after havingbeen positioned by the pallet positioning station 200. The pallet impactstation 100 will be discussed in detail first, followed by the palletpositioning station 200.

The combination of the two stations 100, 200 advantageously allows thelife cycle of the test pallet 50 to be accurately evaluated and in atimely manner. A controller 150 is coupled to the pallet impact station100 and to the pallet positioning station 200 to coordinate andsynchronize operations therebetween with respect to life cycle testingof the test pallet 50.

The pallet impact station 100 includes a frame 102 and at least onependulum swing arm rotatably coupled to the frame 102. In theillustrated embodiment, the at least one pendulum swing arm includes afront pendulum swing arm 104 and a rear pendulum swing arm 106.

A carriage assembly 110 is carried by the front and rear pendulum swingarms 104, 106. The carriage assembly 110 includes a carriage 112, aplurality of counter weights 114 carried by the carriage, and an impactplate 116 carried by the carriage 112.

A latching mechanism 120 extends between the frame 102 and one of thependulum swing arms, such as the rear pendulum swing arm 106. Thelatching mechanism 120 is configured to engage the rear pendulum swingarm 106 when the carriage assembly 110 is in a lowered position, raisethe carriage assembly 110 to a raised positon, and disengage the rearpendulum swing arm 106 at the raised positon so that the impact plate116 strikes the test pallet 50 as the carriage assembly 110 falls.

A movement sensor 140 is carried by the forward pendulum swing arm 104and is configured to generate a signal corresponding to how high thecarriage assembly 110 is raised by the latching mechanism 120. Moreparticularly, the movement sensor 140 is a linear variable differentialtransformer (LVDT) extending between the frame 102 and the forwardpendulum swing arm 104. The controller 150 is configured to operate thelatching mechanism 120, including disengaging the rear pendulum swingarm 106 when a height of the carriage assembly 110 as determined by thegenerated signal corresponds to a desired release height.

The pallet impact station 100 is designed to deliver an impact forcebetween 10 and 2500 joules to the test pallet 50. Typically, an impactforce between 600 to 1100 joules is applied to the test pallet 50 duringa lift cycle test. The delivered impact force is based on the amount ofcounter weights 114 carried by the carriage assembly 110, and how highthe carriage assembly 110 is raised before being released. The carriageassembly 110 may be raised up to 60 degrees, for example.

Each counter weight 114 carried by the carriage 112 weighs 50 pounds,for example. The carriage 112 is sized to carry up to 12 counter weights114. Counter weights 114 are manually added or removed as necessary insupport of the impact forces to be delivered to the test pallet 50.

As noted above, the controller 150 operates the latching mechanism 120to raise the carriage assembly 110, and to release the carriage assembly110 at a desired release height that will deliver a desired impact forceto the test pallet 50. The desired impact force is programmable in thesense that the controller 150 calculates the desired release height todeliver the desired impact force while taking into account the number ofcounter weights 114 in the carriage assembly 110. By changing therelease height of the carriage assembly 110 the amount of the impactforce delivered to the test pallet 50 likewise changes.

The controller 150 knows when the desired release height is reached bythe carriage assembly 110 based on the movement sensor 140 generating asignal corresponding to how high the carriage assembly 110 is beingraised by the latching mechanism 120.

One approach to providing the desired impact force to be applied to thetest pallet 50 is based on the controller 150 interfacing with an RFIDreader 152, which in turn reads an RFID tag 154 carried by the testpallet 50. As the test pallet 50 is moved over the roller conveyor 80towards the pallet impact station 100, the RFID reader 152 reads theRFID tag 154. Information directed to testing of the test pallet 50 isthen provided to the controller 150 by the RFID reader 152. The RFID tag154 also helps to keep track of each individual test pallet 50 duringtesting.

The information on the RFID tag 154 includes the desired impact force tobe applied to the test pallet 50 as well as the dimensions or size ofthe pallet. Dimensions of the test pallet 50 are needed for the palletpositioning station 200 to position the test pallet 50 before eachimpact by the carriage assembly 110. Once the controller 150 receivesthis information it then determines how high the carriage assembly 110is to be raised, based on the amount of counter weights 114 currentlybeing carried, so as to provide the desired impact force on the testpallet 50.

As an alternative to using an RFID tag 154 and an RFID reader 152 tocommunicate with the controller 150, the test pallet 50 may carry a barcode or QR code that is to be read by an optical reader or scanner thatthen communicates with the controller 150. Yet another option is tomanually enter or program the controller 150 with the desired impactforce to be delivered to the test pallet 50.

Referring now to FIGS. 3-5, the illustrated frame 102 for the palletimpact station 100 includes a pair of front legs 101 and a pair of rearlegs 103 each extending from respective surface mounting plates 105 to arectangular-shaped upper support 107. The front legs 101 are verticallypositioned whereas the rear legs 103 are slightly angled or tiltedtowards the front legs 101. Additional side supports 109 extend betweenadjacent legs 101, 103.

The rectangular-shaped upper support 107 of the frame 102 furtherincludes a pendulum swing arm sub-frame support 111 coupled thereto. Theupper portion of the front and rear pendulum swing arms 104, 106 arepivotably coupled to the pendulum swing arm sub-frame support 111.

The front pendulum swing arm 104 includes a pair of spaced apart sidearms 113 with upper and lower cross members 115 extending between theside arms 113. The rear pendulum swing arm 104 is a single arm.

Referring now to FIGS. 6 and 7, the impact plate 116 carried by thecarriage 112 has provisions for carrying one or more impact tines 118.In the illustrated embodiment, there is a pair of spaced apart impacttines 118. The impact tines 118 are representative of the tines on aforklift, for example. The impact tines 118 are not limited to anyparticular shape or size and are generally selected to be representativeof the type of impact test being duplicated on the test pallet 50.

The impact plate 116 may be raised or lowered so that the impact tines118 strike the test pallet 50 at a desired location. For example, theimpact plate 116 may be positioned so that the impact tines 118 strikethe support blocks of the test pallet. Alternatively, the impact plate116 may be positioned so that the impact tines 118 strike an end deckboard or connector boards on the test pallet 50.

The impact plate 116 is raised or lowered by turning a threaded shaft119 clockwise or counter-clockwise. There are a pair of threaded shafts119, one near each end of the impact plate 116. Each threaded shaft 119passes through a respective threaded shaft receiving section 121 coupledto the impact plate 116.

One end of each threaded shaft 119 is coupled to a respective gearsprocket 123. A chain 125 is coupled to the spaced apart gear sprockets123 so that when one of the threaded shafts 119 is rotated, the chain125 will rotate the gear sprocket 123 causing the other threaded shaft119 to likewise rotate. Although not illustrated, a crank or handlewould be coupled to the other end of one of the threaded shafts 119.

The impact tines 118 may also be adjusted left and right. The face ofthe impact plate 116 has a keyed opening, for example, so that theimpact tines 118 may be slid so that they are closer together or spacedfurther apart as desired.

The latching mechanism 120 will now be discussed in more detail inreference to FIGS. 8-13. More particularly, the latching mechanism 120includes a trigger housing 122 and a trigger 124 rotatably positionedwithin the trigger housing. A first actuator 126 moves the trigger 124to engage the rear pendulum swing arm 106 when activated via thecontroller 150 and to raise the carriage assembly 110. A second actuator128 moves the trigger 124 to disengage the rear pendulum swing arm 106when activated via the controller 150 so that the carriage assembly 110falls toward the test pallet 50.

The first actuator 126 may be referred to as the carriage assembly raiseactuator. The second actuator 128 may be referred to as the triggerrelease actuator. The first and second actuators 126, 128 are hydraulicactuators, for example, and are controlled by the controller 150.

Even though the latching mechanism 120 is coupled to the rear pendulumswing arm 106, the forward pendulum swing arm 104 is configured to movewhen the rear pendulum swing arm 106 moves since they are both coupledto the carriage assembly 110. As both of the pendulum swing arms 104,106 are raised, the carriage assembly 110 is likewise raised.

For the trigger 124 to engage the rear pendulum swing arm 106, thecarriage assembly 110 is in a lowered or down positon, which means thatthe forward and rear pendulum swing arms 104, 106 are also in thelowered or down position, as illustrated in FIG. 8. The rear pendulumswing arm 106 includes a trigger catch 130. The first actuator 126 pullsthe trigger housing 122 back towards itself which in turn pulls back thetrigger 124. As the trigger 124 is pulled back it slides over thetrigger catch 130. The trigger 124 is pulled back until it is cleared toengage the trigger catch 130. A spring 132 extends between the triggerhousing 124 and the trigger 122 to bias the trigger towards the triggercatch 130.

After the trigger 124 is ready to engage the trigger catch 130, thefirst actuator 126 pushes the trigger housing 122. Pushing the triggerhousing 122 causes the trigger 124 to push against the trigger catch130. This then causes the rear pendulum swing arm 106 to move to araised position, as illustrated in FIG. 9.

When the carriage assembly 110 is raised to a desired height, asdetermined by the controller 150 via the movement sensor 140, the secondactuator 128 pushes the trigger 124 causing it to disengage from thetrigger catch 130, as illustrated in FIG. 10. Using the second actuator128 to release the trigger 124 allows the carriage assembly 110 tofreefall to the test pallet 50.

Once the trigger 124 clears the trigger catch 130, the carriage assembly110 falls toward the test pallet 50. The forward and rear pendulum swingarms 104, 106 in turn follow the carriage assembly 110, as illustratedin FIG. 11.

The first and second actuators 126, 128 do not add any drag on thecarriage assembly 110 as the carriage assembly 110 falls to the testpallet 50. The latching mechanism 120 thus allows the impact force ofthe carriage assembly 110 to be more accurately controlled since it isnot adding drag to the carriage assembly 110.

As the carriage assembly 110 is freefalling toward the test pallet 50,the latching mechanism 120 follows the carriage assembly 110, asillustrated in FIG. 12. The first actuator 126 again pulls the triggerhousing 122 back towards itself which in turn pulls back the trigger 124until it is cleared to engage the trigger catch 130 again.

An end view of the latching mechanism 120 in FIG. 13 shows that the rearpendulum swing arm 106 includes an opening 134 for the latchingmechanism 120 to move back and forth through. The trigger 124 iscentered within the trigger housing 122, and the trigger catch 130extends across the opening 134. The rear pendulum swing arm 106 includesa pair of side extensions or side plates 107 partially covering thesides of the latching mechanism 120.

Referring now to FIGS. 14 and 15, the pallet impact station 100 furtherincludes a braking mechanism 160 carried by one of the pendulum swingarms, such as the forward pendulum swing arm 104. The controller 150momentarily activates the braking mechanism 160 after the carriageassembly 110 strikes the test pallet 50.

This is done to take the energy out of the carriage assembly 110 afterimpacting the test pallet 50 so as to prevent the carriage assembly 110from bouncing back and striking the test pallet 50 again. After thebraking mechanism 160 releases the forward pendulum swing arm 104, thetrigger 124 from the latching mechanism 120 is moved to engage thetrigger catch 130 so that the carriage assembly 110 may be raised again.

The braking mechanism 160 is configured as a disc brake commonly used oncars and trucks. The braking mechanism 160 includes a partial rotor 162having an arc of about 120 degrees carried by the forward pendulum swingarm 104. Mounted to the frame 102 are the remaining components of thebrake mechanism 160. These components include a brake caliber 164 and apair of brake pads 166. The partial rotor 162 moves in and out of thebrake caliber 164 and the pair of brake pads 166.

A proximity sensor 170 is carried by the frame 102 and is configured togenerate a proximity signal when the forward pendulum swing arm 104passes the proximity sensor prior to the carriage assembly 110 strikingthe pallet. The controller 150 is further configured to momentarilyactivate the braking mechanism 160 after a time delay from receiving theproximity signal.

The pallet positioning station 200 as illustrated in FIG. 2 will now bedisused in more detail. The pallet positioning station 200 is the otherhalf of the life cycle pallet tester, and is configured to repeatedlyposition the test pallet 50 at a same location on a roller conveyor 80before each impact by the pallet impact station 100.

The pallet positioning station 200 includes a frame 204 adjacent theroller conveyor 80 and aligned with the pallet impact station 100, and apallet lift assembly 220 carried by the frame and positioned below theroller conveyor 80.

The pallet lift assembly 220 includes a lift grate 222 moveable betweena retracted position and an extended position. The lift grate 222 isrecessed below an upper surface of the roller conveyor 80 when in theretracted position, and extends above the upper surface of the rollerconveyor 80 when in the extended position so as to lift the test pallet50 off of the roller conveyor 80.

A pallet push arm assembly 240 is carried by the frame 204 and includesa push arm 242 movable between a retracted position and a palletpositioning position. A movement sensor 244 is carried by the frame 204and is configured to generate a signal corresponding to movement of thepush arm 242 when in the pallet positioning position. More particularly,the movement sensor 244 is a linear variable differential transformer(LVDT) extending between the frame 204 and the pallet push arm assembly240.

The controller 150 is configured to move the push arm 242 and the liftgrate 222 to the retracted positions when the test pallet 50 isinitially positioned by the roller conveyor 80 adjacent the palletimpact station 100. The controller 150 is configured to move the liftgrate 222 to the extended position when the test pallet 50 is to bepositioned for impact by the pallet impact station 100, with the testpallet 50 being lifted off of the roller conveyor 80.

The controller 150 is further configured to move the push arm 242 to thepallet positioning position to contact the test pallet 50 and tocontinue moving the test pallet 50 towards the pallet impact station 100until an impact side of the test pallet 50 is aligned with an impactreference plane 90 based on the generated signal as provided by themovement sensor 244 reaching a predetermined value. The impact referenceplane 90 may also be referred to as the zero reference plane whichcorresponds to when the carriage assembly 110 is in its lowermostposition. The tips of the impact tines 118 contact the impact side ofthe test pallet 50 at the zero reference plane so as to provide deliveryof an optimum impact force.

Referring now to FIGS. 16-20, the pallet lift assembly 220 will bediscussed in greater detail. The illustrated pallet lift assembly 220includes a plurality of vertical actuators 224 extending between theframe 204 and the lift grate 222 for moving the lift grate 222 whenactivated via the controller 150 between the retracted position and theextended position. In total there are 4 vertical actuators 224, with oneadjacent each corner of the lift grate 222. The vertical actuators 224are hydraulic actuators, for example, and are controlled by thecontroller 150.

When the lift grate 222 is in the retracted position, the verticalactuators 224 are in the retracted positon, as best illustrated in FIGS.16 and 17. In this position the lift grate 222 is recessed below anupper surface of the roller conveyor 80. This allows the roller conveyor80 to move the test pallet 50 for initially positioning between thepallet impact station 100 and the pallet positioning station 200.

The lift grate 222 comprises a plurality of spaced apart elongated liftelements 226 that are parallel to one another. Each lift element 226 issized to fit between two adjacent rollers 82 that are part of the rollerconveyor 80. The illustrated lift grate 222 includes 10 lift elements226, for example.

The lift elements 226 are held in a spaced apart relationship based onframe elements 228 coupled perpendicular to the lift elements 226. Thevertical actuators 224 are coupled to the frame elements 228. In oneembodiment, a side profile of each lifting element 226 is T-shaped. Inother another embodiment, a side profile of each lifting element 226 isI-shaped.

When the vertical actuators 224 are in the extended positon, asillustrated in FIGS. 21 and 22, the lift grate 222 rises above theroller conveyor 80 to lift the test pallet 50 off of the roller conveyor80. An example lift height of the test pallet 50 is 1 inch above theroller conveyor 80. When the test pallet 50 is lifted off of the rollerconveyor 80, this allows the pallet push arm assembly 240 to then movethe impact side of the test pallet 50 to the impact reference plane 90.

In addition, the test pallet 50 is impacted by the carriage assembly 110when lifted off of the roller conveyor 80. This advantageously ensuresthat the roller conveyor 80 will not cause a drag to be present duringimpact by the carriage assembly 110. If the test pallet 50 were impactedwhen on the roller conveyor 80, then a drag may be present if thebearings of the roller conveyor 80 were getting worn, or if any trash ordebris gets into the tracks of the roller conveyor 80.

Referring now to FIG. 23, the illustrated pallet lift assembly 220 isfurther configured to move the lifting grate 222 in a horizontaldirection. After the test pallet 50 has been raised off of the rollerconveyor 80, the lifting grate 222 is moved towards the pallet push arm242 so that the test pallet 50 is squared with respect to the palletpush arm 242.

For horizontal movement of the lifting grate 222, the pallet liftassembly 220 further includes a radius arm 230 rotatably coupled to theframe 204 and a link 232 that extends between the radius arm 230 and thelift grate 222. At least one horizontal actuator 234 extends between theframe 204 and the radius arm 230 for moving the lift grate 222 whenactivated via the controller 150 in a horizontal direction. Eachhorizontal actuator 224 is a hydraulic actuator, for example, and iscontrolled by the controller 150.

The controller 150 is configured to operate the vertical actuators 224and the horizontal actuator 234 simultaneously. Although notillustrated, there are a plurality of sensors associated with thelifting grate 222 to monitor its position. As an alternative to thecontroller 150 moving the lifting grate in a vertical and/or horizontaldirection so as to reposition the test pallet 50, a test operator maymanually take over control of the pallet lift assembly to controlmovement of the lifting grate 222.

After the pallet lift assembly 220 has squared the test pallet 50 withthe pallet push arm 242, then the pallet push arm assembly 240 isoperated by the controller 150 to push the test pallet 50 towards theimpact reference plane 90, as illustrated in FIG. 24. The controller 150knows when the impact side of the test pallet 50 reaches the impactreference plane 90.

The controller 150 receives the size or dimensions of the test pallet 50prior to repositioning. This information may be stored in an RFID tag154 carried by the test pallet 50, and communicated to the controller150 via an RFID reader 152. The controller 150 subtracts the distance tothe impact reference plane 90 by the width of the test pallet 50 todetermine how far to push the test pallet 50. As the pallet push armassembly 240 is moving the test pallet 50, the movement sensor 244provides a distance signal to the controller 150.

As illustrated in the figures, one or more unit loads 260 may be placedon the cargo layer of the test pallet 50. The unit load 260 is tosimulate a customer's product being carried by the test pallet 50. Theunit loads may vary between 250 to 2500 pounds, for example.

Prior to impact by the carriage assembly 110, the unit loads 260 on topof the test pallet 50 need to be repositioned. This is accomplished witha stationary unit load push bar 270 coupled to the frame 102 of thepallet impact station 100, as illustrated in FIGS. 25-26.

The stationary unit load push bar 270 is above the height of the testpallet 50, and extends past the impact reference plane 90 so as to makecontact with the unit loads 260. As the pallet push arm assembly 240pushes the impact side of the test pallet 50 towards the impactreference plane 90, the unit loads 260 contact the stationary unit loadpush bar 270. This results in the unit loads 260 being repositioned onthe test pallet 50.

The pallet push arm assembly 240 includes a pair of spaced apart radiusarms 248 rotatably coupled to the frame 204, and a pair of respectivelinks 250 extending between the pair of radius arms 248 and the palletpush arm 242. A pair of actuators 252 extend between the pair of radiusarms 248 and the pallet push arm 242 for moving the test pallet 50 whenactivated via the controller 150.

After the impact side of the test pallet 50 is aligned with the impactreference plane 90, and the units loads 260 have been repositioned aswell, the pallet push arm assembly 240 pulls the pallet push arm 242away from the test pallet 50, as illustrated in FIG. 27. The pallet pusharm 242 is returned back to its zero reference point as determined bythe controller 150 reading the signal generated by the movement sensor244. The test pallet 50 is now ready for impact by the carriage assembly110.

Another aspect is directed to a method for operating the pallet impactstation 100, as will now be discussed in reference to the flowchart 300in FIG. 28. From the start (Block 302), the method includes operatingthe latching mechanism 120 at Block 304 to engage the at least onependulum swing arm 106 when the carriage assembly 110 is in a loweredposition, and operating the latching mechanism 120 at Block 306 to raisethe carriage assembly 110 to a raised positon. The signal generated bythe movement sensor 140 corresponding to how high the carriage assembly110 is raised by the latching mechanism 120 is monitored at Block 308.The method further includes operating the latching mechanism 120 todisengage from the at least one pendulum swing arm 106 at Block 310 whena height of the carriage assembly 110 corresponds to a desired releaseheight so that a predetermined impact force strikes the test pallet 50.The method ends at Block 312.

Another aspect is directed to a method for operating the palletpositioning station 200, as will now be discussed in reference to theflowchart 330 in FIG. 29. From the start (Block 332), the methodincludes moving the pallet push arm 242 and the lift grate 222 to theretracted positions to receive the test pallet 50 for positioning atBlock 334. The lift grate 222 is moved to the extended position at Block336 when the test pallet 50 is to be positioned for impact by the palletimpact station 100, with the test pallet 50 being lifted off of theroller conveyor 80 by the lift grate 222. The pallet push arm 242 ismoved to the pallet positioning position at Block 338 to move the testpallet 50 towards the pallet impact station 100 until an impact side ofthe test pallet 50 is aligned with an impact reference plane 90. Themethod ends at Block 340.

Yet another aspect is directed to a method for testing a pallet 50 usingthe pallet tester 100, 200, as will now be discussed in reference to theflowchart 360 in FIG. 30. From the start (Block 362), the methodincludes moving the pallet push arm 242 to the retracted position atBlock 364 to receive the pallet 50 for positioning, and moving thepallet push arm 242 to the pallet positioning position at Block 366 tomove the pallet 50 towards the pallet impact station 100 until an impactside of the pallet 50 is aligned with an impact reference plane 90. Thelatching mechanism 120 is operated at Block 368 to raise the carriageassembly 110, and to release the carriage assembly 110 when a height ofthe carriage assembly 110 corresponds to a desired release height sothat a predetermined impact force strikes the pallet 50 at the impactreference plane 90. The method ends at Block 370.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims.

That which is claimed:
 1. A pallet positioning station for positioning apallet to be impacted by a pallet impact station, and comprising: apallet push arm assembly adjacent the pallet impact station andcomprising a pallet push arm movable between a retracted position and apallet positioning position; and a controller configured to perform thefollowing: move said pallet push arm to the retracted positions toreceive the pallet for positioning, and move said pallet push arm to thepallet positioning position to position the pallet towards the palletimpact station for impact.
 2. The pallet positioning station accordingto claim 1 further comprising a pallet lift assembly comprising a liftgrate moveable between a retracted position and an extended position,and wherein said controller is further configured to perform thefollowing: move said lift grate to the retracted position to receive thepallet for positioning; and move said lift grate to the extendedposition when the pallet is to be positioned for impact by the palletimpact station.
 3. The pallet positioning station according to claim 2wherein said controller is further configured to position the pallettowards the pallet impact station for impact until the pallet is alignedwith an impact reference plane.
 4. The pallet positioning stationaccording to claim 2 further comprising a frame adjacent the palletimpact station, with said pallet lift assembly being carried by saidframe.
 5. The pallet positioning station according to claim 2 whereinsaid lift grate comprises a plurality of spaced apart elongated liftelements, with each respective lift element sized to fit between twoadjacent rollers of a roller conveyor.
 6. The pallet positioning stationaccording to claim 2 wherein said pallet lift assembly further comprisesa plurality of vertical actuators for moving said lift grate whenactivated via said controller between the retracted position and theextended position.
 7. The pallet positioning station according to claim6 wherein said pallet lift assembly further comprises at least onehorizontal actuator for moving said lift grate in a horizontal directionbetween an impact reference plane and said pallet push arm; and whereinsaid controller is further configured to activate the at least onehorizontal actuator to move the lift grate in the horizontal directiontowards the pallet push arm so that the pallet contacts said pallet pusharm before said pallet push arm is moved to the pallet positioningposition.
 8. The pallet positioning station according to claim 7 whereinsaid pallet lift assembly further comprises: a radius arm rotatablycoupled to a frame; and a link extending between said radius arm andsaid lift grate; with said at least one horizontal actuator extendingbetween the frame and said radius arm.
 9. The pallet positioning stationaccording to claim 7 wherein said controller is further configured tooperate said plurality of vertical actuators and said at least onehorizontal actuator simultaneously.
 10. The pallet positioning stationaccording to claim 7 wherein said plurality of vertical actuators andsaid at least one horizontal actuator each comprises a hydraulicactuator.
 11. The pallet positioning station according to claim 1wherein said pallet push arm assembly comprises: a pair of spaced apartradius arms rotatably coupled to a frame; a pair of spaced apart linksextending between said pair of radius arms and said pallet push arm; anda pair of actuators extending between the frame and said pair of radiusarms for moving the pallet when activated via said controller.
 12. Thepallet positioning station according to claim 1 further comprising aframe adjacent the pallet impact station, with said pallet push armassembly being carried by said frame.
 13. The pallet positioning stationaccording to claim 1 further comprising a movement sensor configured togenerate a signal corresponding to movement of said pallet push arm whenin the pallet positioning position; and wherein said controller isfurther configured to move said pallet push arm in the palletpositioning position until the generated signal reaches a predeterminedvalue, with the predetermined value corresponding to when an impact sideof the pallet is aligned with an impact reference plane.
 14. The palletpositioning station according to claim 13 wherein said movement sensorcomprises a linear variable differential transformer (LVDT) extendingbetween said frame and one of said radius arms.
 15. The palletpositioning station according to claim 1 wherein said controller isfurther configured to move said pallet push arm back to the retractedposition after an impact side of the pallet is aligned with an impactreference plane.
 16. The pallet positioning station according to claim 1wherein the pallet carries a unit load during impact with the palletimpact station; wherein the pallet impact station comprises a stationaryunit load push bar adjacent an impact reference plane; and as saidcontroller moves said pallet push arm in the pallet positioning positionto move the pallet, the unit load contacts the stationary unit load pushbar as an impact side of the pallet continues to move towards the impactreference plane.
 17. A pallet positioning station comprising: a palletpush arm movable between a retracted position and a pallet positioningposition; a movement sensor configured to generate a signalcorresponding to movement of said pallet push arm when in the palletpositioning position; and a controller configured to perform thefollowing: move said pallet push arm to the retracted position toreceive the pallet for positioning, and move said pallet push arm to thepallet positioning position to position the pallet towards a palletimpact station based on the generated signal reaching a predeterminedvalue.
 18. The pallet positioning station according to claim 17 whereinsaid controller is further configured to move said pallet push arm backto the retracted position after an impact side of the pallet is alignedwith an impact reference plane.
 19. The pallet positioning stationaccording to claim 17 further comprising a lift grate moveable between aretracted position and an extended position, and wherein said controlleris further configured to perform the following: move said lift grate tothe retracted position to receive the pallet for positioning; and movesaid lift grate to the extended position when the pallet is to bepositioned for impact by the pallet impact station.
 20. The palletpositioning station according to claim 19 wherein said lift gratecomprises a plurality of spaced apart elongated lift elements, with eachrespective lift element sized to fit between adjacent rollers of aroller conveyor carrying the pallet for impact by the pallet impactstation.